Recommendation ITU-T G.989.2 specifies the physical media dependent (PMD) layer requirements for a passive optical network system with a nominal aggregate capacity of 40 Gbit/s in the downstream direction and 10Gbit/s in the upstream direction, hereinafter referred to as NG-PON2. NG-PON2 is a flexible optical fibre access network capable of supporting the bandwidth requirements of mobile backhaul, business and residential services. Furthermore, this recommendation describes optional configurations to extend beyond this nominal capacity as the G.989 series of standards allows for multiple upstream and downstream line rates. NG-PON2 wavelength plan is defined to enable the coexistence through wavelength overlay with legacy PON systems (see [ITU G.989.1]). The transmission convergence (TC) layer is based on Recommendation ITU-T G.987.3, with unique modifications for NG-PON2 captured in Recommendation ITU-T G.989.3. The ONU management and control interface (OMCI) specifications are described in Recommendation ITU-T G.988 for NG-PON2 extensions. This recommendation specifies the characteristics of hybrid time and wavelength multiplexed channels, hereinafter referred to as TWDM PON. The characteristics of, optional, tunable point-to-point wavelength overlay channels are also described, hereinafter referred to as PtP WDM PON. The TWDM PON described in this Recommendation represents a further development from the systems described in the ITU-T G.984 and G.987 series. To the greatest extent possible, this Recommendation retains the requirements of ITU-T G.984.1 and G.987.1 to ensure maximal reuse of existing technology and compatibility with deployed optical access systems and optical fibre infrastructure.

G.989.2 (G.ngpon2.2) was consented on 6 December 2013 and submitted to Last Call on 16 January 2014, and was then forwarded to Study Group, which decided on 4 April 2014 to reinitiate the Last Call process.